Since the first case reported in Dec 2019, the novel Coronavirus Disease (COVID-19) has made the world a pandemic era. Till 4 Oct 2020, there have been 34,724,785 confirmed cases of COVID-19, including 1,030,160 deaths, according to WHO [1]}. Accurate lesion localisation and segmentation methods are in huge demand to aid the fast disease diagnosis and stage monitoring. Among different diagnostic imaging modalities, computed tomography (CT) has proven itself to be effective and been widely used for the assessment and evaluation of disease evolution [2]}, [3]}. Patchy ground-glass opacitity (GGO) with consolidation is often been found from CT images as a typical sign of lung infection. Thus, the quantitative evaluation of such lung lesions can help diagnosis.
